MAR 01, 2019 1:06 PM PST

As the Waves Subside--Two Years after the Detection of Gravitational Wave GW170817

An artistic impression of two merging neutron stars (NASA)

GW170817 is the code name given to a gravitational wave (GW) signal back in August 2017. With a duration of about 100 seconds, the GW bears the characteristics of binary stars resolving around and getting drawn closer to closer to each other. It was later confirmed that the signal was the result of the merger of two neutron stars in the NGC 4993, a lens-shaped galaxy140 million lightyears away. 

Preceded by the other five GW observations, which all happened in this decade, GW170817 was a scientifically significant event on its own. However, what made it a watershed for the field of astrophysics is that the collision of the binary giants produced more than just ripples in the space-time continuum: it also released a wide spectrum of electromagnetic radiation, including gamma ray, x-ray, and near inferred. These signals were captured at a slightly later time than the arrival of GW170817, by 70 observatories all over the globe and in the space. 

This ground-breaking event ushered in a new era of Multi-messenger astronomy. The journal Science recognized GW170817 and the subsequent global observation campaigns as the Breakthrough of the Year for 2017.

What's more, two years after the original observation, scientists are still making new discoveries into the nature of neutron star collision by combing through the data recorded during the initial observations. 

Just seconds after GW170817 was detected, a short gamma-ray burst (GRB) was also identified by NASA's Fermi Gamma-ray Space Telescope and ESA's International Gamma-ray Astrophysics Laboratory, two space observatories that were in Earth's orbit.

The gamma-ray burst overlapped the gravitational wave position direction-wise, validating the theory that neutron star mergers generate short gamma-ray bursts. By carefully examining the characteristics of the recorded gamma ray, scientists now believe that another two earlier signals, GRB 080503 and GRB 130603B,  could have also originated from the merger of binary neutron stars, or one neutron star and a black hole.

The fading gamma ray from GRB 170817 (NASA/ESA)

The merger that yielded GW170817 also resulted in a massive black hole, which astronomers believe bears 95% of the mass of its parents. A recent publication in the journal Science, suggested that  the black hole emitted a structured jet of material hours after its birth. Although some scientists speculated that the immediate swelling after the merge may shape like a uniformly expanding cocoon, base on the analysis of the radio afterglow recorded in the subsequent observation campaign by 32 radio telescopes around the globe, the research group behind the paper concluded that the electromagnetic signals originated from jets of 5% materials that got spilled out from the black hole. These jets escaped the surrounding vicinity at close to light speed.

As scientists continue to dig through the original data, they are hopeful that the landmark event GW170817 will keep producing more fascinating discoveries that can revolutionize our understanding of astrophysics

What We Learned About Neutron Star Collisions Since 2017 (Anton Petrov) 

Source: Science

About the Author
  • Graduated with a bachelor degree in Pharmaceutical Science and a master degree in neuropharmacology, Daniel is a radiopharmaceutical and radiobiology expert based in Ottawa, Canada. With years of experience in biomedical R&D, Daniel is very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles. The recurring topics in his Chemistry & Physics trending news section include alternative energy, material science, theoretical physics, medical imaging, and green chemistry.
You May Also Like
OCT 21, 2019
Space & Astronomy
OCT 21, 2019
Here's Why NASA Wants to Crash a Spacecraft Into an Asteroid
Yes, you read that right; NASA would like to slam a purposefully built spacecraft into the surface of an asteroid. While this idea might seem like a substa...
NOV 11, 2019
Chemistry & Physics
NOV 11, 2019
Scientists Bolstered Water-based Hydrogen Production with a 10-Dollar Magnet
Hydrogen is dubbed the clean energy of the future because its consumption leads to no carbon emission but only water. But things are not always what they s...
DEC 04, 2019
Cancer
DEC 04, 2019
Photon up-conversion for new cancer treatments
Scientists from the University of California, Riverside and The University of Texas at Austin have made a breakthrough in materials science that has signif...
JAN 13, 2020
Space & Astronomy
JAN 13, 2020
Lunar Dust is Actually Quite Dangerous to Humans
Most people have a tendency to think that lunar dust isn’t any different than the dirt found here on Earth, but quite the opposite is true. In fact,...
JAN 16, 2020
Chemistry & Physics
JAN 16, 2020
Self-healable Sweat Sensor Fears No Wear and Tear
Sweat can provide a lot of information about a person's health. One of the current trends in wearable technology is to incorporate sweat sensing mechan...
JAN 29, 2020
Chemistry & Physics
JAN 29, 2020
Milk, a Controversial Food?
When it comes to foods with a controversial reputation, milk isn't your usual suspect. First and foremost, we humans are mammals and breast milk is a q...
Loading Comments...